Acceleration sensitive variable clock



Feb. 23, 1965 F. H. SWAIM ETAL 3,170,404

ACCELERATION SENSITIVE VARIABLE CLOCK Filed March 17., 1955 I N VEN TOR 9 Arthur Hausner Frank H Swa/m ATTORNEYS United States Patent ACCELERATION SENSITIVE VARIABLE CLQCK Frank H. Swaim, Silver Spring, Md, and Arthur Hausner, Washington, D.C., assignors to the United States of America as represented by the Secretary of the Army Filed Mar. 17, 1955, Ser. No. 495,077

, 4 Claims. (Cl. 102-84) (Granted under Title 35, US. Code (1952), sec. 266) The invention described herein may be manufactured by or for the Government for governmental purposes without the payment to us of any royalty thereon.

This invention relates to clocks and more particularly to an acceleration settable clock adapted to provide variable delayed arming for ordnance projectile fuzes.

There are at least two reasons for maintaining a projectile fuze unarmed for an interval of time following projectile launching. One reason is to provide bore and muzzle safetyto prevent injury to the gun crew in the event of a premature function. The other is to reduce the effective lost of fuzes due to early fuze function; Concerning the latter factor, it is desirable to set the clock in such a manner that the fuze will arm just prior to expected normal fuze function depending upon estimated fligh time to target.

One object of this invention is a new and novel mechanical clock adapted to provide variable delayed arming for ordnance projectile fuzes.

Another object is a clock adapted to store some of the energy of setback to be used to cause the fuze to arm just prior to the time of anticipated fuze function.

A further object is a clock adapted to store an amount of energy proportional to the setback force developed.

An additional object is a rugged inexpensive reliable clock adapted to provide variable arming delay within narrow limits.

of the clock and fuze arming rotor taken on line 1-1 of FIG. 2.

FIGURE 2 is a view of the clock taken on line 2-2 of FIG. l. I p

FIGURE 3 is a view of the fuze arming rotor taken on line 33 of FIG. 1. v

In the preferred embodiment of the invention the elementsof a; mechanical clock, indicated generallyby numeral 10, are housed within'frame members 11 and 12, FIG. 1. Eccentrically balanced upon and adapted to rotate with shaft 13, journaledwithin said frame members, is segment gear or weight 14 which is biased in the counterclockwise direction as indicated by arrow 15, FIG. 2. The biasing means is helical spring 16, FIG. 1, one end of which engages shaft 13 and the other end of which engages frame 11. In the static condition gear 14 is prevented from rotating counterclockwise by lever 17 which is mounted upon and adapted to turn with shaft 17a, shaft 17a being .journaled within frame members 11 and 12. Lever 17 rests against stop 18a. Stop 18!) arrests the counterclockwise movement of lever 17 after the lever is released when gear 14 rotates clockwise. Lever 17 is biased in the counterclockwise direction, arrow 19, by helical spring 20 which has one end engaged with shaft 17a and the other end engaged with frame 11. V

Segment gear 14 engages pinion 21 which is mounted upon and adapted to turn with shaft 22, the shaft being journaled within frames 11 and 12. Mounted upon shaft 22, also, and adapted to turn therewith is plate 23 which is provided with internal ratchet teeth 24. Gear 25 is mounted upon shaft 22 but is free to turn with respect 3,170,404 Patented Feb. 23, 1965 thereto. Gear 25 has pin 25 affixed thereto, pawl 27 being mounted upon but rotatable with respect to pin 26, pawl 27 being biased against ratchet teeth 24 by torsion spring 28. Spring 28 is supported by posts 29 and 30 affixed to gear 25, FIG. 2.

Gear 25 engages pinion 31 which is mounted upon and adapted to turn with shaft 32, the shaft being journaled within frames 11 and 12. Gear 33 is mounted upon shaft 32 and adapted to turn therewith and is engaged with pinion 34 which is mounted upon and adapted to turn with shaft 35, the shaft being journaled within framesll and 12.

Mounted upon shaft 35, also, and adapted to turn therewith is escapement wheel 36 which engages and cooperates with pallet 37, the pallet being mounted upon and adapted to oscillate with shaft 38 which is journaledwithin frames 11 and 12.

Fuze arming rotor 39 is mounted upon and adapted to turn with shaft 49 which is journaled within frame members 11 and 41, the rotor being biased in the clockwise direction, arrow 42, by helical spring 43, one end of which engages shaft 40 and the other end of whichengages frame 41. Rotor 39 is normally prevented from turning by the engagement of half-shaft 44 with detent 45 provided in the said rotor, half-shaft 44 being an extension of shaft 13.

When the projectile, not shown, is fired, the setback force acting upon clock 10 causes the eccentrically mounted segment gear 14 to rotate in the clockwise direciton as indicated by arow 46, FIG. 2. Spring 16, which is prewound somewhat, is wound an additional amount depending upon the clockwise angular movement of gear movement of gear 14 is a function of the time-acceleration integral and the movement will increase as this integral increases. The value of the setback force or this timeacceleration integral will be proportional to the initial velocity of the projectile. As the angular movement of gear 14 winds the spring 16, the energy stored in the spring will increase as said integral increases and be a function of said integral.

As gear 14 rotates, pinion 21, engagedtherewith, turns shaft 22 which causes plate 23 to turn. Plate 23 turns free of restraint of the remainder of the gear train inasmuch as pawl 27 slips with respect to ratchet teeth 24 when plate 23 rotates in the counterclockwise direction.

Plate 23 acts as 'a flywheel to slow the clockwise rotation of gear 14, to limit the rotation of gear 14 toa 'small' portion of one revolution during setback, and to supply themomentum necessary to carry gear- 14 through, an additional angle aftersetback abates vWere there no restraining forces such as a spring or the moment of inertia of the various elements, gear 14 would turn through an angle substantially independent of the setback forces being applied. The flywheel movesgear 14 through an additional angle after setback abates, depending upon the rotational speed of the flywheel at that time,

it being a consideration that the greater the angle through which gear 14 turns, provided the teeth of gear 14 do not run out with respect to pinion 21, the greater the timing accuracy of the clock. g 7

When gear 14 turns clockwise'lever 17 is freed to rotate counterclockwise, as indicated by arow 19, FIG. 2,

clear of the rotational path of gear 14, coming to rest against stop 18b.

When the force of setback abates, spring 16drives segment gear 14 in the opposite direction, counterclockwise as indicated by arrow 15. Its time rate of rotation in the counterclockwise direction issubstantially constant, depending upon the design of the system. Therefore the energy which has been stored in the spring 16-is released at a substantially constant time rate.

3,170, ioa

The regulation of the speed of rotation of gear 14 is controlled by the clock escapement which includes escapement wheel 36 and pallet 37. Gear 14 turns pinion 21 which causes plate 23 to turn. As plate 23 rotates in the clockwise direction, gear 25 is caused to rotate therewith, pawl 27 now engaging ratchet teeth 24. Gear 25 turns pinion 31 which causes gear 33 to turn, and gear 33 turns pinion 34 which causes escapement wheel 36 to turn. Escapernent wheel 36 cooperates with pallet 37 to regulate the speed of the elements of clock 1th, gear 14 being the element requiring regulation.

Segment gear 14, on its return trip, moves past its at rest position, lever 17 having revolved clear of its path of rotation. Shaft 13 and half-shaft 44 turn with gear 14.

Half-shaft 44 having rotated first in the counterclockwise "direction as indicated by arrow 47, FIG. 3, as gear 1'4 moved clockwise to wind spring 15, reverses its direction of rotation, as seen by arrow 48, as spring 16 drives gear 14in the opposite direction. When half-shaft 44 moves to the position indicated by the dotted contour, rotor 39 is freed to revolve clockwise to arm the fuze. Thus it will be seen that the fuze does not arm until after all the energy which was stored in spring 16 by the movement of gear 14 has been released.

The manner in which half-shaft 44 cooperates with rotor 39 provides an additional safety for the system.

In order that rotor 39 be released to move into its armed position, not only must half-shaft 44 rotate clear of the rotational path of the rotor but also the half-shaft must be turning at a regulated speed at the time it rotates clear of the rotational path of rotor 3?. Otherwise, before "rotor 39 overcomes its own inertia and begins to turn, 'half-shaft 44 will have spun through its rotor release position to a position wherein it once again engages detent 45 to prevent rotor 39 from turning.

It will be apparent that the embodiment shown is only exemplary and that various modifications can be made :in construction and arrangement within the scope of the invention as defined in the appended claims.

We claim: 1. In an ordnance projectile fuze having an arming rotor, a variable delay clock comprising an eccentrically 'balanced first gear on a first shaft, the said gear adapted to rotate in a first direction when subjected to a force of 'setback, spring means somewhat prewound associated with said gear adapted to wind an additional amount when said gear'rotates in the first direction, the additional winding being proportional to the amount of rotation, means preventing said gear from rotating in the opposite direction until it has rotated in the first direction, said adfirst direction, to limit that rotation to a small portion of one revolution during setback, and to carry said gear through an additional angle after setback abates, escapement means adapted to regulate the speed of rotation of said gear as it turns in the opposite direction, a plurality of gears and pinions linking said flywheel with said escapement means, clutch means adapted to disengage said escapement means from said flywheel when said gear turns in the first direction and to reengage said escapement means with said flywheel when said gear turns in the opposite direction, and means adapted to actuate said fuze arming rotor after said gear has rotated in the opposite direction through an angle somewhat greater than the angle through which it rotated in the first direction.

2. An arming device for an ordnance projectile fuze comprising: a frame, a first gear on a first shaft mounted for rotation on said frame, a spring biasing said gear in a first direction, said first gear being eccentrically balanced so that an acceleration applied to the frame in a predetermined direction will cause the gear to rotate against the spring bias, a second shaft mounted for rotation on said frame, a pinion attached to the second shaft with the teeth meshing with the teeth of the first gear, a second gear mounted for rotation on said second shaft, a one way clutch means for causing said second gear to turn with said second shaft when the first gear rotates in said first direction and for permitting said second shaft to rotate freely of said second gear'when the first gear is rotated against said spring bias, and means for regulating the speed of rotation of said second gear.

3. The invention according to claim 2 wherein said arming device further comprises: means mounted on said frame for preventing said first gear from rotating in said first direction until after said acceleration has been applied.

4. The invention according to claim 2 wherein said arming device further comprises: a spring biased rotor mounted for rotation on said frame, said rotor being in 'a first position and adapted to rotate to an armed position; and means responsive to said first gear rotating in said first direction for releasing said rotor from said first position so that said rotor will rotate to said armedposition.

References Cited by the Examiner UNITED STATES PATENTS 2,076,613. 4/37 Bleecker 10284 2,094,032 9/37 Zornig 10271 2,485,362 10/49 OBlin 102-78 X 2,537,953 1/51 Andrews 102-78 2,536,437 2/52 Rabinow 10278 2,710,578 6/55 Rabinow 10278 SAMUEL FEINBERG, Primary Examiner. SAMUEL BOYD, Examiner. 

2. AN ARMING DEVICE FOR AN ORDNANCE PROJECTLE FUZE COMPRISING: A FRAME, A FIRST GEAR ON A FIRST SHAFT MOUNTED FOR ROTATION OF SAID FRAME, A SPRING BIASING SAID GEAR IN A FIRST DIRECTION, SAID FIRST GEAR BEING ECCENTRICALLY BALANCED SO THAT AN ACCELERATION APPLIED TO THE FRAME IN A PREDETERMINED DIRECTION WILL CAUSE THE GEAR TO ROTATE AGAINST THE SPRING BIAS, A SECOND SHAFT MOUNTED FOR ROTATION ON SAID FRAME, A PINION ATTACHED TO THE SECOND SHAFT WITH THE TEETH MESHING WITH THE TEETH OF THE FIRST GEAR, A SECOND GEAR MOUNTED FOR ROTATION ON SAID SECOND SHAFT, A ONE WAY CLUTCH MEANS FOR CAUSING SAID SECOND GEAR TO TURN WITH SAID SECOND SHAFT WHEN THE FIRST GEAR ROTATES IN SAID FIRST DIRECTION AND FOR PERMITTING SAID SECOND SHAFT TO ROTAGE FREELY OF SAID SECOND GEAR WHEN THE FIRST GEAR IS ROTATED AGAINST SAID SPRING BIAS, AND MEANS FOR REGULATING THE SPEED OF ROTATION OF SAID SECOND GEAR. 